The volume of a cone of height 9cm is 1848cm3. Find its radius. [Take π = 22/7]
7cm
14cm
28cm
98cm
196cm
Correct answer is B
1/3 πr2 x 9 = 1848
3 x πr2 = 1848 r2 = 1848/3 x 7/22 r = 14
Volume of a cone=13πr2h
13×227×r2×9=1848
r2=1848×722×3
r2=196∴
3.5cm
7cm
14cm
28cm
32cm
Correct answer is C
Curved surface area of a cylindrical tin = 2\pi rh
\therefore 2\pi rh = 704cm^2
2 \times \frac{22}{7} \times 8 \times h = 704
h = \frac{704 \times 7}{2 \times 22 \times 8}
h = 14cm
16/3cm
15/3cm
16/5cm
8/3cm
16/10cm
Correct answer is A
L = θ/360 x 2πR = 240/360 x 2 x 22/7 x 8/1 ... (1)
This must be equal to the circumference of the circle which is 2πr = 44R/7 .... (2)
equate (1) and (2)
r = 16/3 = 51/3
Solve the equation \frac{m}{3} + \frac{1}{2} = \frac{3}{4} + \frac{m}{4}
-3
-2
2
3
4
Correct answer is D
\frac{m}{3} + \frac{1}{2} = \frac{3}{4} + \frac{m}{4}
\frac{m}{3} - \frac{m}{4} = \frac{3}{4} - \frac{1}{2}
\frac{m}{12} = \frac{1}{4}
4m = 12 \implies m = 3
What must be added to the expression x^2 - 18x to make it a perfect square?
3
9
36
72
81
Correct answer is E
x^2 - 18x to be a perfect square.
(\frac{b}{2})^2 is added to ax^2 + bx + c in order to make it a perfect square.
x^2 - 18x + (\frac{-18}{2})^2
= x^2 - 18x + 81